FAT Filesystem and Linux - Commonalities

Commonalities

As mentioned previously, all of the Linux filesystem drivers support all of the three File Allocation Table sizes, 12-bit, 16-bit, and 32-bit. Other common features that they all support are various Linux mounting options (specified with the -o option to the mount command):

uid and gid

These two options tell the filesystem driver to set the (default, in the case of umsdos) owner ID and group ID to be a single, specified, value for all files in the volume. Both IDs are specified as numeric values (as to be found in the /etc/passwd file). So, for example, to specify to the vfat filesystem driver that all files and directories are to have owner ID 745 and group ID 15, the mount command would be invoked as mount -t vfat -o uid=745,gid=15 . Linux filesystem drivers do not at present incorporate support for file/directory passwords on FAT12/FAT16/FAT32 volumes and multi-user world/group/owner access permissions for read/write/delete/execute rights on FAT12/FAT16 volumes as implemented in various operating systems of the Digital Research family, including DR-DOS, PalmDOS, Novell DOS, OpenDOS, FlexOS, Concurrent DOS, Multiuser DOS, System Manager and REAL/32.

umask

This option sets the umask to apply globally to all files in the volume. For example, to specify to the vfat filesystem driver that no "group" or "other" access is to be allowed, the mount command would be invoked as mount -t vfat -o umask=077 .

conv

This option specifies file content conversion semantics. It is possible for the filesystem drivers to convert the newline conventions in files, between LF termination and CRLF termination, on the fly as files are read and written. By default this conversion is entirely disabled. The filesystem drivers can perform conversion for some files, attempting to auto-detect what files to convert based upon the extension portion of the filename, or globally for all files. These three conversion levels are specified as conv=b (for "binary"), conv=a (for "auto-detect"), and conv=t (for "text"), respectively. The latter two options carry an inherent risk of corrupting non-text file data. No conversion at all is the default.